view tests/test-bdiff.py @ 33116:6c113a7dec52

tests: use the system hg for examining the local repository

Most test scripts use "hg" to interact with a temporary test repository.
However a few tests also want to run hg commands to interact with the local
repository containing the mercurial source code.  Notably, many of the
test-check-* tests want to check local files and commit messages.

These tests were previously using the version of hg being tested to query the
source repository.  However, this will fail if the source repository requires
extensions or other settings not supported by the version of mercurial being
tested.  The source repository was typically initially cloned using the system
hg installation, so we should use the system hg installation to query it.

There was already a helpers-testrepo.sh script designed to help cope with
different requirements for the source repository versus the test repositories.
However, it only handled the evolve extension.  This new behavior works with
any extensions that are different between the system installation and the test
installation.

from __future__ import absolute_import, print_function
import collections
import struct
import unittest

from mercurial import (
    mdiff,
)

class diffreplace(
    collections.namedtuple('diffreplace', 'start end from_ to')):
    def __repr__(self):
        return 'diffreplace(%r, %r, %r, %r)' % self

class BdiffTests(unittest.TestCase):

    def assert_bdiff_applies(self, a, b):
        d = mdiff.textdiff(a, b)
        c = a
        if d:
            c = mdiff.patches(a, [d])
        self.assertEqual(
            c, b, ("bad diff+patch result from\n  %r to\n  "
                   "%r: \nbdiff: %r\npatched: %r" % (a, b, d, c[:200])))

    def assert_bdiff(self, a, b):
        self.assert_bdiff_applies(a, b)
        self.assert_bdiff_applies(b, a)

    def test_bdiff_basic(self):
        cases = [
            ("a\nc\n\n\n\n", "a\nb\n\n\n"),
            ("a\nb\nc\n", "a\nc\n"),
            ("", ""),
            ("a\nb\nc", "a\nb\nc"),
            ("a\nb\nc\nd\n", "a\nd\n"),
            ("a\nb\nc\nd\n", "a\nc\ne\n"),
            ("a\nb\nc\n", "a\nc\n"),
            ("a\n", "c\na\nb\n"),
            ("a\n", ""),
            ("a\n", "b\nc\n"),
            ("a\n", "c\na\n"),
            ("", "adjfkjdjksdhfksj"),
            ("", "ab"),
            ("", "abc"),
            ("a", "a"),
            ("ab", "ab"),
            ("abc", "abc"),
            ("a\n", "a\n"),
            ("a\nb", "a\nb"),
        ]
        for a, b in cases:
            self.assert_bdiff(a, b)

    def showdiff(self, a, b):
        bin = mdiff.textdiff(a, b)
        pos = 0
        q = 0
        actions = []
        while pos < len(bin):
            p1, p2, l = struct.unpack(">lll", bin[pos:pos + 12])
            pos += 12
            if p1:
                actions.append(a[q:p1])
            actions.append(diffreplace(p1, p2, a[p1:p2], bin[pos:pos + l]))
            pos += l
            q = p2
        if q < len(a):
            actions.append(a[q:])
        return actions

    def test_issue1295(self):
        cases = [
            ("x\n\nx\n\nx\n\nx\n\nz\n", "x\n\nx\n\ny\n\nx\n\nx\n\nz\n",
             ['x\n\nx\n\n', diffreplace(6, 6, '', 'y\n\n'), 'x\n\nx\n\nz\n']),
            ("x\n\nx\n\nx\n\nx\n\nz\n", "x\n\nx\n\ny\n\nx\n\ny\n\nx\n\nz\n",
             ['x\n\nx\n\n',
              diffreplace(6, 6, '', 'y\n\n'),
              'x\n\n',
              diffreplace(9, 9, '', 'y\n\n'),
              'x\n\nz\n']),
        ]
        for old, new, want in cases:
            self.assertEqual(self.showdiff(old, new), want)

    def test_issue1295_varies_on_pure(self):
            # we should pick up abbbc. rather than bc.de as the longest match
        got = self.showdiff("a\nb\nb\nb\nc\n.\nd\ne\n.\nf\n",
                            "a\nb\nb\na\nb\nb\nb\nc\n.\nb\nc\n.\nd\ne\nf\n")
        want_c = ['a\nb\nb\n',
                  diffreplace(6, 6, '', 'a\nb\nb\nb\nc\n.\n'),
                  'b\nc\n.\nd\ne\n',
                  diffreplace(16, 18, '.\n', ''),
                  'f\n']
        want_pure = [diffreplace(0, 0, '', 'a\nb\nb\n'),
                     'a\nb\nb\nb\nc\n.\n',
                     diffreplace(12, 12, '', 'b\nc\n.\n'),
                     'd\ne\n',
                     diffreplace(16, 18, '.\n', ''), 'f\n']
        self.assert_(got in (want_c, want_pure),
                     'got: %r, wanted either %r or %r' % (
                         got, want_c, want_pure))

    def test_fixws(self):
        cases = [
            (" \ta\r b\t\n", "ab\n", 1),
            (" \ta\r b\t\n", " a b\n", 0),
            ("", "", 1),
            ("", "", 0),
        ]
        for a, b, allws in cases:
            c = mdiff.fixws(a, allws)
            self.assertEqual(
                c, b, 'fixws(%r) want %r got %r (allws=%r)' % (a, b, c, allws))

    def test_nice_diff_for_trivial_change(self):
        self.assertEqual(self.showdiff(
            ''.join('<%s\n-\n' % i for i in range(5)),
            ''.join('>%s\n-\n' % i for i in range(5))),
                         [diffreplace(0, 3, '<0\n', '>0\n'),
                          '-\n',
                          diffreplace(5, 8, '<1\n', '>1\n'),
                          '-\n',
                          diffreplace(10, 13, '<2\n', '>2\n'),
                          '-\n',
                          diffreplace(15, 18, '<3\n', '>3\n'),
                          '-\n',
                          diffreplace(20, 23, '<4\n', '>4\n'),
                          '-\n'])

    def test_prefer_appending(self):
        # 1 line to 3 lines
        self.assertEqual(self.showdiff('a\n', 'a\n' * 3),
                         ['a\n', diffreplace(2, 2, '', 'a\na\n')])
        # 1 line to 5 lines
        self.assertEqual(self.showdiff('a\n', 'a\n' * 5),
                         ['a\n', diffreplace(2, 2, '', 'a\na\na\na\n')])

    def test_prefer_removing_trailing(self):
        # 3 lines to 1 line
        self.assertEqual(self.showdiff('a\n' * 3, 'a\n'),
                         ['a\n', diffreplace(2, 6, 'a\na\n', '')])
        # 5 lines to 1 line
        self.assertEqual(self.showdiff('a\n' * 5, 'a\n'),
                         ['a\n', diffreplace(2, 10, 'a\na\na\na\n', '')])

if __name__ == '__main__':
    import silenttestrunner
    silenttestrunner.main(__name__)